The invention relates to a device for measuring the temperature of metal melts and, more particularly, for continuously measuring the temperature of a molten metal through the wall of a metallurgical container or vessel. The invention further relates to the use of porous purging plugs in such containers or vessels.
Porous purging plugs have a key role when manufacturing steel. One or more porous purging plugs are replaceably mounted in the bottom of a ladle or other metallurgical vessel. In the vessel, various high-temperature chemical processes are carried out in which the porous purging plug is crucial, since inert gas, such as argon, is conveyed through the plug for purging the molten metal. Generally, bubbles are created by the purge gas, which cause a vortex of steel around the plug, leading to a buildup of metal on the plug. Chemical erosion of the plug is caused by metal build-up and physical erosion is caused by continuous washing of the steel against the plug. Thus, the uppermost portion of the purge plug is typically heavily worn during the metallurgical process. Accordingly, the purge plug has to be replaced regularly by a new purge plug when its height has shrunk to a minimum permissible level. Conventional purge plugs, as such, are not highly reliable components for vessels used in manufacturing steel.
It is also generally known from the prior art to use or arrange a thermocouple device in a wall of a metallurgical vessel. In conventional arrangements, the thermocouple device may be susceptible to chemical and mechanical damage due to the molten metal environment in which it is used. Also, it may take a relatively long period of time for the thermocouple device to reach its equilibrium temperature with the metal melt, so that measurements of the melt cannot be taken quickly and efficiently.